Question

A locomotive of mass m= 1.134 X 10⁵ kg uses 37.8 kW of power to accelerate at a constant rate for 15.0 s.

a) The locomotive has an initial velocity of 0.500 m/s east. Calculate the locomotive’s speed after 15.0 s.

After 15.0 s, the locomotive travels east at a constant speed and then collides and couples with a train of four cars. Each of the cars has half the mass of the locomotive. Before the collision, the train was travelling east at 1.60 m/s. Assume the train tracks have negligible friction.

b) Calculate the final speed of the coupled train.

c) Calculate the change in kinetic energy during the collision.

Answer 1

Mass of Locomotive, m= 1.134x10 kg power, P: 37.8KW = 37.8 xión time -t: 15.0 sec workdone ,W= plt)- 37.8x16x15= 5.67x10 J Initial speed of Locomotive, (i = 0.500mls According to work - energy theorem. change in t.E = work done zmenen Lemvi w u - 0² = 20 E 2N+ci? = 1245-678709, asook final speed Of = 3.20 mls] 2x5.67X/05 +0.5002 7:134X105 346,05 мозг оf bеѕіn -- х 44 of each cal. M = 4* m 2m relocity of train before collision , U= 1.60 m/s According to principal of conservation of momentum Initial momentum before callidions finele Momentum after collinon 2m07 muf = (2m +m) V V zmut mup 24+Of 3 2nim finde upce s COUPE fine sfeed of coubled - V - 2U+Up. 261.60)+ 3.20. 213410 3 tran 7 3 change in kE: Initril k.En final ke © = (omjuz- & amtm) 12 = m(1F+202 312)= 4x1.19981569:28 +2X46-22x2-133 967685